In this day, it is more and more difficult for an adult to keep an eye on a child. Children have a strong desire to explore when they are in an environment that has lots of activity or objects around, such as a shopping mall. Unfortunately, it is also at this time that a monitoring adult is most distracted. Accordingly, it is easy for the monitoring adult to loose sight of the child and thereby, lead to frantic searching of the immediate area to find the child. Accordingly, it is desirable to determine when a child leaves the area of an adult that is minding the child.
This desire to determine when the monitored device leaves the vicinity of the monitoring device is not limited to the above parent/child scenario. There are many instances when it would be desirable to determine when a monitored object leaves the vicinity of a monitoring device. It is not even essential that the monitored device be the device that is in motion. For example, in a case wherein a person desires to keep track of an object, such as luggage in an airport, it may be desirable for the person to be aware of whether the luggage is in their immediate vicinity. To achieve this desirable result, the person may attach a monitored device to the luggage or place the monitored device within the luggage. In this way, in an event wherein the person is moving about the airport, for example while interacting with airport personnel, the person would also have a means to determine that the luggage is close and not outside an acceptable range from the person.
A conventional monitoring device is known that sets off an alarm when a monitored device leaves the vicinity of a monitoring device. In operation, the monitoring device receives a periodic or continuous signal transmitted by the monitored device. In the above adult/child scenario, the adult carries the monitoring device and the child carries the monitored device. When the monitored device moves a given distance from the monitoring device, the monitoring device will no longer receive the signal. When the monitoring device no longer receives the signal from the monitored device, the monitoring device emits an audible signal to indicate that the monitored device, and the child carrying the monitored device, has moved the given distance, or more, from the monitoring device. This signal acts to alert the adult that the child is no longer in close proximity.
A problem exists with this system in that although the adult is alerted that the child is no longer in close proximity, the adult has no idea in which direction the child is located. In an open area, this does not present a problem since the adult would just look around to determine where the child is located. However, in an area that has many objects around, such as aisles and sales displays, as in the case of the above-mentioned shopping mall, the child may not be directly viewable from the adults vantage point. Accordingly, once again the adult is put in a position to have to wander around the vicinity to determine the current location of the child.
Conventional devices are known that enable determination of a location of the device. For example, a global positioning satellite (GPS) device has a receiving antenna that receives signals from three or more GPS satellites to determine the location of the GPS device within some error tolerance. However, typically a GPS device does not transmit location information to a secondary device. In one known system, utilized for automobile location identification, On-Star™ transmits GPS information to a central monitoring station for the purposes of identifying the location of the automobile for example in the event of an accident. However, this system has many drawbacks in that the system is large and complex and does not lend itself to a simple, cost effective system. Further, the On-Star™ device does not determine when a monitored device leaves the vicinity of a monitoring device.
Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art.